If upon payment or tender to any such mortgagee of the amount of the value or compensation so agreed upon or determined such mortgagee shall fail to convey or release to the promoters of the undertaking, or as they shall direct, his interest in the lands in respect of which such compensation shall so have been paid or tendered, or if he shall fail to adduce a good title thereto to the satisfaction of the promoters of the undertaking, it shall be lawful for the promoters of the undertaking F1to pay into the F2Senior Courts the amount of such value or compensation; and the making of payment to the mortgagee or into the F2Senior Courts shall be accepted by such mortgagee in satisfaction of his mortgage debt, so far as the same will extend, and shall be a full discharge of the portion of the mortgaged lands so required from all money due thereon; and it shall be lawful for the promoters of the undertaking, if they think fit, to execute a deed poll, duly stamped, in the manner herein-before provided in the case of the purchase of lands by them; and thereupon such lands shall become absolutely vested in the promoters of the undertaking, as to all such estate and interest as were then vested in the mortgagee, or any person in trust for him, and in case such mortgagee were himself entitled to such possession they shall be entitled to immediate possession thereof; nevertheless every such mortgagee shall have the same powers and remedies for recovering or compelling payment of the mortgage money, or the residue thereof, (as the case may be,) and the interest thereof respectively, upon and out of the residue of such mortgaged lands, or the portion thereof not required for the purposes of the special Act, as he would otherwise have had or been entitled to for recovering or compelling payment thereof upon or out of the whole of the lands originally comprised in such mortgage.