If I pushed the throttles all the way forward, i.e. firewall (which used to be a proper SOP term in some airlines), I would use max available thrust, which would possibly be above max rated thrust. This could lead to a complete failure of the engine/s if unlucky, and most surely would lead to some damage or life-time degradation, but could be used in a situation where the only other alternative was ground impact.
You obviously do what you must to keep from "spoiling your whole day", but you'd have to be VERY unlucky to break an engine in the minute or two "max available thrust" is used. I've seen engines abused per above that required nothing more than a special inspection, or perhaps some shroud/air seal replacement to restore performance, but no distress beyond that.
But use your good judgement.
