If you're already having these doubts then until you get more info about it or get convinced by whoever, I'd steer clear.
I'm sure there's no obligation to do it so you shouldn't feel bad if you decline.
The current employment agreement is probably the least of your worries in terms of making your decision. Probably just some declaration of interest thing to fill out.
Agree with @Rab. It's something you'd need to be fully sure of doing (and you don't sound like you are!) but while you're contemplating that anyway, always good to take care of yourself and protect yourself. And if that means avoiding investments that don't sound too worthwhile, so be it!