“[Plaintiff] claims that [supervisor] gave her an ultimatum that, in effect, forced her to miss her regularly-scheduled physical therapy session in order to keep her job. Specifically, [Plaintiff] was told that if she missed the upcoming Wednesday for therapy, or any day for that matter, she would be fired. This allegation is sufficient[] . . . to constitute a constructive discharge.” McGregor v. United Healthcare Servs., Inc., CIV. A. H-09-2340, 2010 WL 3082293, at *4 (S.D. Tex. Aug. 6, 2010). “[Supervisor]’s alleged ultimatum was explicit, and [Plaintiff] clearly could not comply with it . . . .” Id.