be- - in (LS 79; CSOL I 507; CSOL II 424 – 425)

PWS
*bi/ba - in; by means of (instrumental) (Arakelova 2001:31, Kogan 2015: 77)
An eventual derivation from either *bayt- ‘house’ or *bwˀ ‘to come’ is not to be excluded (cf. Voigt 1999:37, 39‒40, Blažek 2007:31).
In several languages (Ugr., Pho., Heb., Arm., Har., Gur.) this preposition has a meaning “from”, nearly opposite to the locative meaning “in”. These forms could be ascribed to a separate homonymous preposition which could be united with ESA forms of the type bn with the same meaning (Sab. bn, Min. bn, Qat. bn). However, it is essential that Akk. ina possesses both of these meanings (Arakelova 2001:33).