I feel like you guys are giving too much credit to IFT, or indirectly to experience. You are gonna see both things in IFT and 911. The great thing about IFT is that you are gonna have a diagnosis, and you are gonna have a chart with a review of systems that elaborates on how they came up with that diagnosis. There is gonna be a lot of fluff or extra information in that chart that is gonna make it difficult to associate things with a certain disease especially if the patient has multiple diseases/conditions, which many IFT patients do. The same is true for medications, the patient usually has a bunch of medications that are gonna make difficult to associate it with a certain disease or condition unless you specifically ask what the medication is for or it's listed with the MAR (medication administration record). I think the issue with skills is the fact that few patients will only have one problem where it will be easy to associate a sign, symptom, or medication with that one problem so it will be difficult to make this association even with experience or visually seeing it.
As far skills, you aren't gonna perform a lot of skills in both IFT or 911 as an EMT because an EMT doesn't have that many skills. The primary one you are gonna do on both are vital signs. In 911, you will probably do more backboarding, splinting, bandaging, and electing to start oxygen administration versus IFT, but lets face it, those are easy skills that you either don't need practice on (administering oxygen) and will probably be inappropriate even though it's tradition/protocols (backboarding and oxygen administrating) and you can easily practice the rest (bandaging, backboard, splinting) during your free time.
There is one thing I really like about IFT over 911 although I don't have a lot of 911 experience other than observation (I have been exclusively been doing IFT for several years, no 911) and that is working on a dedicated critical care transport (CCT) unit with either a CCT-Paramedic or a CCT-RN. I wouldn't say I learned that much more things clinically, but did learn more about equipment commonly used on those calls: ventilators and IV pumps. Both equipment as a paramedic (if you become one and one is allowed to be used in your area) are gonna be equipment/service dependent so you may learn how to use it in one area, but another area or company is gonna use something different. Although I cannot do much other than prepare the ventilator or IV pump for the CCT-P or CCT-RN, which is minimal (you input numbers, plug in some tubing, but you don't actually switch it over or anything like that... the CCT-P and CCT-RN have to make sure all the numbers are correct/sane and switch it over themselves), I did get to learn what each mode and setting means (ie AC vs SIMV vs CPAP + PS, volume control vs pressure control, what is pressure support, what is PEEP, what is FiO2, etc) and have been exposed to medications that CCT-P or CCT-RN can administer in addition to the standard drugs that paramedics can give (we have a much bigger drug box although still very limited compare to the rest of the US). So that I definitely really do like about IFT CCT vs 911 ALS, and I will be sad that one day I might be a paramedic, but the extra drugs I know (the basics) about I won't be allowed to administer or transport with unless I become a CCT-P or CCT-RN. Paramedics in my area also don't use IV pumps or ventilators so we cannot set that up on a 911 call or do that for IFT calls either unfortunately. :[
I am gonna say that you should do what others recommend. Read the chart particularly the review of systems part (it's the part where they break up everything by system when describing the signs and symptoms). Check out the MAR and look up the drugs using a PDR (physician desk reference). Continue to do your own assessment on a patient when appropriate and take vital signs. Don't be afraid to learn outside of your scope when you get a chance (eg if the patient has an IV, don't be afraid to learn how to tell IV gauge size, how to describe the location of the IV, what's infusing, and what rate... transporting a patient with infusion of basic isotonics is actually allowed in a lot of places for EMTs even though a lot of EMTs don't realize it, or another example is working on CCT and learning what a drug is that was administer or infusion, learning what each thing on a ventilator, IV pump, etc. means).
In the end, I think working IFT is BEST for learning operations of an ambulance ie where hospitals are, door codes, capability of the hospital, policies and protocols, how to use a gurney, learning the roads, etc. The clinical things you learn from experience (whether working 911 or IFT) is probably gonna be slightly different, but come at a different rate (you might see pursed lips, accessory muscle use etc. more on 911 for example, but 911 might see a lot of things where they won't be able to associate it with something for sure because diagnostics haven't been done or no diagnosis by a physician has been done yet). The quickest way to learn clinical things will be to learn it on your own reading books, through active discussion of patient assessments, and skills will probably be infrequently used so you will have to practice them on your own or with friends at a school or during your free time at work if allowed. That way when it actually does happen in front of you, you will know what you are seeing rather than guessing (in 911) or trying to decipher a chart (in IFT).
Not at my current company, but my previous one. We used to practice CPR, backboarding, splinting, and patient assessment frequently when we were posted at the station. I felt like that benefited me way more than when I had an actual call at IFT or what I saw during my observations with 911 units. We took pride in practicing during our down time because it was a very slow station. Many 911 calls I saw were usually simple things like coryzal symptoms (gotta give a shout out to Brandon Oto from emsbasics.com and is a poster here for that word, hehe), psychiatric (just like BLS psychiatric transports we do), and minor trauma (scrapped knee, twisted ankle, etc). Your (limited) skills will deteriorate even if on 911 unless you put extra effort into practicing it or discussing it (skills like CPR, you're gonna need practice, discussion talking about things you messed up on/could have done better on, and you are gonna need to mentally prepare yourself if you are gonna be in charge of organizing things.. I mean mentally not like emotional, but ask yourself what needs to be done and run a fake scenario in your head, practice it with different amount of resources eg you can pretend to have a whole resuscitation team that's capable of everything, do a scenario where it's just you and your partner and no one else is coming, or maybe you can pretend to be a paramedic and have an EMT partner, or maybe both you and your partner are paramedics, come up with issues like you guys weren't able to get an IV successfully, the patient was a traumatic patient, or the patient wasn't in vfib/vtach - most people practice CPR as if it's only vfib/vtach only so they aren't prepared to go through the algorithm PEA/asystole or aren't prepared to think further than "this is related to cardiac ischemia" rather than think other H & Ts). This is not just limited to single patients either, think about doing fake scenarios in your head of running an MCI... are you gonna be the IC? Is it just you and your partner? What resources will you need? What kinda MCIs might you bump into or be pulled into while at work (eg if you work near an airport, will you respond to an airplane crash? I work near three large airports and three small ones). I work near a lot of chemical plants too. Maybe terrorism?
I am not gonna downplay experience. Experience is great. There are some things you are gonna see more frequently than others, and there are some things you might see only once or twice in your life and won't get another chance to be ready for it so your only way is to practice mentally and read about it/research it or practice it with others if possible.
Anyhow, I am rambling now....
In regard to diverting, what UnkiEMT said is excellent. Is the patient gonna die in 10 minutes (or is there an obvious problem pretty much)? If not, continue transporting, lol.
A lot of that information, you should be able to obtain prior to transporting.