While mash out is a good idea, it won't screw your beer if you forget to mashout with BIAB. I think if you put the bag back in while the wort was under 170 and raised the temp, you might be ok. I would be more concerned with what was in the sink you put the bag in. Hopefully you didn't have soap in there or some weird floaty. For me, when I mashout, I usually target 168 to give myself a 2 degree buffer before flirting with the too much tannin temps. RDWHAHB and see what happens. Right good notes and remember this for next time.