Summary: Senior engineer left after being lied to by the management. Soon I might be approached to fill the role. How can I ensure same bad things won't happen to me?
I'm working for a division of a large company that has recently fallen on hard times. Instead of coming together, several senior leaders have gone into a "cover your own rear" mode, and fractured our division further. This recently boiled over when a very senior engineer left the company (on good terms officially, but I learned via various means that senior management baited this individual with a large promotion as part of a "Thanatos gambit": if he/she works 3x time and saves the day, the company does well without having to pay much extra to this person; if he/she fails, they get to be the scapegoat and get fired earlier than others to help with layoff budget issues that will soon arise). When this individual learned that they'd not only be assuming all the risk and that management lied about the associated bonuses, raises, etc.; he/she left immediately. This left us in a bad spot as this person basically is a 10-person team on his/her own (management was stupid to provoke this person).
Several other senior engineers, including myself, were recently competing to take over for this person, but we've learned that several other engineers are also preparing to leave the company too (some for their own reasons, some for the absolute s***-show that was just demonstrated). We're also quite demoralized that a position we've sought for so many years might be "poisoned", and that management would treat such a promotion as a joke like they did with our former colleague.
A couple colleagues and I have been approached about taking over for our former colleague. I could perhaps grow into this person's former role over a few years, but am not yet ready to just step in for them. Also, I don't trust management 100% with all the recent changes (managers being shuffled around like cards at a poker table). Is there a polite way to ask my boss and his boss, without dooming whatever career I have left at this company, whether or not they plan to also fxxx me over (and demanding all changes in pay, responsibility, etc. be provided in writing with a signature in advance of discussion)? Clearly such a request doesn't show much trust on my part, but I have none.
Edit
I tried to get everything in writing, in advance, and my managers just shied away angrily. When I pressed the issue, it was made clear to me that I was no longer a "candidate" for their non-promotion. Time to join the exodus.