The OP asked if a husband being placed in cheirim is a valid reason for a wife to demand a get even if her husband doesn’t want to give one. As mdd and others have responded, there are only certain reasons halacha requires a husband to give a get even if he doesn’t want to. In other cases, where halacha doesn’t require an involuntary get, the wife cannot, under halacha, force her husband to give her a get. Since a husband being placed in cheirim is not one of the reasons a wife can demand a get, she is not a “mesorevet get” in that case. (Like hello99 pointed out, the term “agunah” is always incorrect in cases other than when the husband is lost.)
