Estimation of the amount of mass ejected from the envelope during the AT 2018bwo LRN event based on a simple energy formalism, (see Eq. (1)–(4)). The envelope structure was taken from a binary MESA model with a 15 M_⊙ donor shown in Fig. 10. The black line shows the energy required to unbind and bring to infinity a portion of the outer envelope with mass M_ej. Coloured lines correspond to the orbital energy transferred by accretors with different masses when inspiraling deeper into the primary’s envelope, up to the radius when the outer shell has mass M_ej.