the temple had only one key, but thirteen gates...
what trickled, then gushed out after the key was thrown to heaven?
(this page continues the list of the 13 temple gates, including the water gate. there is a brief description that in the future a thin trickle of water will flow out from the Holy of Holies, expanding to eventually forming a strong unstoppable current. there is another story that when Jehochian, one of the last kings of Judah, realised that the Babylonians were coming and the temple will be destroyed, he took the temple key and threw it up to heaven. a hand came out and caught it. After the destruction of the temple, the tribe of Judah - the Jews - went to Babylon... and thus began diaspora.
The 13 gates in this collage are 13 frontispieces from various editions of the Talmud. which often depict a gate. and on whose pages a single verse can expand into a wide ocean of interpretation and discussion....)